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UWorld mixed > test #18 4.6 > Flashcards

test #18 4.6 Flashcards

1
Q

which antigen on e.coli is the major virulent determinant for meningitis

A

K-1 antigen (capsular). inhibits complement and phagocytosis.

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2
Q

how does e.coli lead to meningitis

A

invade blood stream from nasopharynx or GI tract. travel hematogenously to meninges.

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3
Q

what rxn results from a beesting?

A

local allergic rxn: type 1 HSR. direct crosslinking of IgE on mast cells & basphils –> histamine, proteases, heparin, leukotrienes, and prostaglandins –> wheal (urticaria: erythematous papule or plaque w/ central pallor)

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4
Q

TNF-alpha made by..

A

made by macrophages and mast cells. signals for apoptosis of tumor cells & activation of inflammatory cells (like CD4+ T lymphocytes, neutrophils, fibroblasts, endothelial cells, and hematopoietic cells)

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5
Q

name 2 conditions w/ elevated TNF-alpha. rx?

A

in many inflammatory conditions: rheumatoid and psoriatic arthritis. can be elevated in type IV HSR

rx: inflixamab and entanercept

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6
Q

inflixamab and etanercept?

A

humanized anti-TNFalpha immunolobulins that reduce inflammation in rheumatoid and psoriatic arthritis – prevent induction of inflammation

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7
Q

Th1 vs. Th2 immune responses

A

Th1, secrete IL-2 induces macrophage and cytotoxic T-cell rxn

Th2, secrete IL-4, induces humoral immunity.

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8
Q

anal canal extends from __ to __? upper & lower canal?

A

extends from perineal flexure (anorectal junction) to perianal skin (anal verge). divided to upper and lower canal.

upper canal: above pectinate line: hindgut
lower canal: invagination of surface ectoderm.

junction between these canals – closed during embryonic life by anal membrane at level of pectinate line.

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9
Q

imperforate anus? associated w.?

A

spectrum of disorders w/ abnormal development of anorectal structures.

MOST OFTEN associated w. GENITOURINARY TRACT MALFORMATIONS: urorectal, urovesical, or urovaginal fistulas.

can see meconium discharge from urethra or vagina

also: renal agenesis, hypospadias, epispadias, bladder extrophy

other congenital abnormalities w/ imperforate anus VACTERL:
vertebral defects, anal atresia, cardiac anomalies, tracheoesophageal fistula, esophageal atresia, renal anomalies, limb anomalies

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10
Q

VACTERL syndrome?

A

vertebral defects, anal atresia, cardiac anomalies, tracheoesophageal fistula, esophageal atresia, renal anomalies, limb anomalies.

much less common than isolated urogenital anomalies associated w/ imperforate anus.

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11
Q

if there is a 95% confidence interval that a value falls between 2 numbers..

A

there is at least a 5% chance the value falls outside this range, some equal to p value (probability that results obtained were due to chance alone)

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12
Q

hawthorne effect

A

tendency of a study population to affect an outcome due to KNOWLEDGE OF BEING STUDIED

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13
Q

pygmalion effect

A

describes researcher’s belief in the efficacy of treatment that can potentially affect the outcome

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14
Q

schilling test: purpose of intramuscular injection of cobalamin w/ radiolabeled cobalamin?

A

ensure that radiolabeled will be excreted in urine for measurement.

high B12 in urine – B12 deficiency.
low – either instrinsic fxr or absorption problem.
low post administration of intrinsic factor – intestinal malabsorption

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15
Q

causes of intestinal malabsorption of B12 (3)

A

pancreatic insufficiency, intestinal bacterial overgrowth, ileal disease

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16
Q

3 rx for acute gouty arthritis

A

(1) 1st line: NSAIDs (2) colchine and (3) glucocorticoids

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17
Q

impt side effects of colchines (3)

A

nausea, abdominal pain, diarrhea

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18
Q

hepatic encephalopathy

A

REVERSIBLE decline in neurologic function precipitated by hepatic damage

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19
Q

how does ammonia enter circulation

A

via GI tract; enterocytic catabolism of glutamine and bacterial catabolism of dietary protein in colon –> portal circulation to liver for detox into urea.

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20
Q

precipitants of hepatic encephalopathy (w/ underlying liver cirrhosis)

A

stressors that alter ammonia balance: GI bleed (hematemesis), hypovolemia, hypokalemia, metabolic alkalosis, hypoxia, sedative usage, hypoglycemia, infxn

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21
Q

rx: for hyperammonia

A

administer continuous disaccharide (lactulose): bacterial action on lactulose results in acidification of colonic contents – convert absorbable ammonia into nonabsorbable ammonium (ammonia trap)

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22
Q

accumulation of BUN can indicate what 3 things?

A

(1) renal failure (2) heart failure (3) dehydration

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23
Q

describe neuropathy in diabetes (3)

A

(1) symmetric peripheral neuropathy (2) mononeuropathy (3) autonomic neuropathy

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24
Q

which CN is most common affected in diabetes? what type of injury? presentation

A

CN III; ischemic. note somatic / parasympathetic – diff blood supplies. diabetic neuropathy.

affects SOMATIC – ptosis w/ down & out gaze. accomodation in tact

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25
Q

nerve compression vs. diabetic ischemic injury to CNIII

A

nerve compression: both SOMATIC and parasympathetic; ptosis, down & out gaze, fixed dilated pupil, no accomodation

nerve ischemia: SOMATIC, ptosis w/ down & out gaze

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26
Q

somatic component of CNIII works on? parasympathetic component?

A

somatic: (1) extraocular muscles: inferior, superior, medial, inferior oblique. (2) levator palpebrae
parasympathetic: sphincter of iris & ciliary muscle

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27
Q

how can CN III be compressed (2)

A

(1) PComm aneursym (2) transtentorial herniation

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28
Q

describe hemosiderin

A

hemoglobin-derived marker of iron accumulation.

golden-yellow brown pigment that may appear in either granular or crystalline form.

aggregation of ferritin micelles

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29
Q

melanin formed when..

A

tyrosinase converts tyrosine to dihydroxyphenylalanine

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30
Q

why is right main bronchus more prone to foreign body aspiration?

A

(1) larger diameter (2) shorter (3) orientaed more vertically than left

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31
Q

aortic rupture most commonly caused by…

A

MVA. sudden deceleration causes diff rates of deceleration between heart (fixed position) and aorta. often at AORTIC ISTHMUS (between ascending/descending, distal to left subclavian branch point)

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32
Q

back pain not relieved by rest / change in position = typical presentation for..

A

neoplastic bone disease

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33
Q

metastatic prostate cancer has a strong predilection for.. lesions are..?

A

bones (esp axial skeleton).

BLASTIC mets (sclerotic) detected by radionuclide bone scanning

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34
Q

presenting symptoms of prostate cancer

A

urinary frequency, hesitancy, nocturia, hematuria.

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35
Q

markers of different phases of prostate cancer (3)

A

(1) increased PSA (2) advanced disease, increased prostatic acid phosphatase (when tumor penetrates capsule of prostate) (3) increased alkaline phosphatase (due to bone mets)

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36
Q

most common inflammatory arthritis of lumbosacral spine

A

ankylosing spondylitis )decrease range of motion in lumbosacral spine)

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37
Q

clearance mechanism used by lung for particles (1) 10-15uM (2) 2.5-10uM and (3) <2uM

A

(1) large, 10-15uM: trapped in upper respiratory tract (2) medium, 2.5-10: enter trachea and bronchi, cleared by mucocilary transport. (3) finest particles reach terminal bronchioli and alveoli – phagocytized by macrophages

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38
Q

describe pathophysiology of pneumoconiosis

A

interstitial lung fibrosis, secondary to inhalation of fine inorganic dust.

alveolar macrophage takes up dust, become activated, release cytokines –> induce injury and inflammation of alveolar cells

also release growth factors (PDGF, IGF) –> stimulate fibroblasts to proliferate and produce collagen

INFLAMMATION & FIBROSIS

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39
Q

describe t-tubule contact in skeletal muscle

A

one t-tubule contacts 2 terminal cisterns (of sarcoplasmic reticulum) forming a triad at the jxn of the A band and the I band

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40
Q

uniform distribution of t-tubules ensures…

A

depolarizing signal reaches each fiber at the same time – coordinated muscle contraction

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41
Q

myotonic dystrophy..

A

autosomal dominant. trinucleotide expansion. impaired relaxation after a single contraction

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42
Q

2 main bone types in adults? characterize the two?

A
  • trabecular (aka spongy, cancellous)
  • cortical bones (aka long bones)

trabecular = composes 15% of total skeleton by weight, but metabolically more active bc of surface area

cortical bones = serve as mechanical support & sites of muscle attachment

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43
Q

common sites for osteoporotic fractures? (2)

A

1st: vertebral bodies (predominately trabecular)
2nd: neck of femur ( 50% trabecular, 50% cortical)

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44
Q

increased deposition of unmineralized osteoid

A

characterestic of vitamin D deficiency.

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45
Q

bone resorption in hyperparathyroidism vs. osteoperososis

A

hyperPTH: primarily CORTICAL (subperiosteal thinning).
osteoperosis: primarily TRABECULAR

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46
Q

persistence of primary, unmineralized spongiosa in medulla canals?

A

osteopetrosis (primary spongiosa should be replaced w/ bone marrow)

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47
Q

major virulence factor for strep pyogenes? what does it do (4)

A

protein M. inhibits phagocytosis & activation of complement & cytotoxic for neutrophils & mediator of bacterial attachment

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48
Q

is bacterial hyaluronate immunogenic?

A

no, present in capsule and has antiphagocytic activity, but cannot be distinguished from human CT ground substance

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49
Q

streptolysin O

A

in s. pyogenes. oxygen-labile immunogenic extracellular protein. lyses erythrocyte (b-hemolytic) and PMNs.

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50
Q

DNase

A

in s. pyogenes. extracellular enzyme, depolymerizes viscous DNA in pus & disintegrates PMNs. allows streptococcus to move more freely

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51
Q

streptokinase

A

in s. pyogenes. extracellular enzyme that catalyzes plasminogen to plasmin. results in fibrin digestion & facilitating the spread of streptococci.

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52
Q

target of type-specific humoral immunity to s. pyogenes?

A

against protein M

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53
Q

5 clinical presentations of fragile X syndrome

A

typical: MR, facial deformities, macroorchidism

(1) mild mental retardation, speech & language delay, autistic behaviour, ADHD.
(2) large ears, long face, prominent mandible, cleft palate.
(3) large testes
(4) mitral valve prolapse
(5) short height, joint laxity (hyper extensible), scoliosis, pes cavus (high arch foot), double-jointed thumbs, single palmar crease

54
Q

47 XYY karyotype

A

associated w/ (1) tall stature (2) severe acne (3) mild delays in both motor and language development. possibly associated w/ more aggression?

55
Q

47 XXX karyotype

A

clinically silent, maybe lower IQ?

56
Q

testicular feminization syndrome (complete androgen insensitivity)

A

normal external female genitalia, but completely absent wolffian & mullerian ducts

57
Q

glyburide

A

sulfonylurea

58
Q

acarbose & miglitol

A

alpha-glucosidase inhibitor. decrease activity of dissacharides on intestinal brush border.

59
Q

glucagon-like polypeptide-1 (GLP-1)? mechanism? example?

A

incretin hormone. secreted by intestinal L cells in response to food intake. decreases glucose by inducing SATIETY.

acts through GPCRs: adenylyl cylase

exenatide

60
Q

exenatide

A

long-acting GLP-1 analogue, approved for rx of type 2 diabetes w/ suboptimal glucose control, despite adequate doses of metformin & sulfonylureas

61
Q

thiazolidinediones

A

decrease insulin resistance. bind to peroxisome proliferator activated receptor gamma (PPAR-gamma). belongs to nuclear receptor superfamily: regulates gene expression after ligand binding.

62
Q

biguanide

A

metformin. alter intracellular enzymes. reduces glucose levels by enhancing glycolysis & inhibiting gluconeogenesis.

63
Q

1, 25-dihydroxycholecalciferol (25-OH-D3) is..

A

calcitriol – active form of vitamin D

64
Q

renal osteodystrophy

A

bone resorption due to high PTH. causes bone pain, signs of osteopenia & soft tissue calcification of x-ray

65
Q

calcitonin

A

parafollicular cells in thyroid – in response to elevated calcium. (1) promotes bone mineralization and (2) reduces intestinal absorption of Ca2+

66
Q

recurrent sinusitis in a young caucasian raises suspicion for..

A

cystic fibrosis.

67
Q

note: possible for mild CF to present w/ near normal sweat test. how is CF diagnosed?

A

yes, mild mutations.

diagnose: nasal transepithelial potential difference (charge on respiratory epithelial surface as compared to interstitial fluid). CF: more NEGATIVE surface due to increased luminal Na+ ABSORPTION.

68
Q

normal CFTR fxn on Cl- and Na+ in exocrine glands. result of defect?

A

normally (1) SECRETES Cl- into lumen (2) tonic inhibitory effect on opening of apical Na+ channel (inhibit absorbtion Na+ into cell)

defect: no Cl- secretion and increased Na+ absorption –> dehydrated mucus & widened negative transepithelial potential difference.

(sweat glands different)

69
Q

CFTR in most exocrine glands vs. SWEAT glands

A

in sweat glands, CFTR absorbs Cl- (not secrete it)

70
Q

most significant causes of vitamin A deficiency

A

malnourishment and fat malabsorption (cystic fibrosis, cholestatic liver disease)

71
Q

clinical manifestations of vitamin A deficiency (3)

more unusual findings?

A

night blindness, complete blindness, and xeropthalmia

unusual findings: bitot’s spots (abnormal squamous cell proliferation and keratinization of conjunctiva), corneal perforation, ketatomalacia, nonspecific dermatologic abnormalities, humoral & cell-mediated immune system inhibition via damage done to phagocytes and T cell lymphocytes

72
Q

bitot’s spots

A

abnormal squamous cell proliferation and keratinization of conjunctiva. seen in vitamin A deficiency

73
Q

vitamin supplementation for rx of measles? how does it help?

A

vitamin A. reduces time to recovery from pneumonia & diarrhea, as well as length of hospital stay and risk of death.

postulate: vitamin A resolves virally-induced hyporeteinemia, though not confirmed.

74
Q

aldolase B converts..

A

fructose-1-phosphate into DHAP / glyceraldehyde. trioskinase –> glyceraldehyde 3-phosphate —–> pyruvate.

75
Q

3 enzymes needed for metabolism of fructose

A

(1) fructokinase (2) aldolase B (3) triokinase

76
Q

reducing sugars

A

fructose, glucose, galatose

77
Q

urine dipstick tests specifically for glucose bc..

A

glucose oxidase. will not test + for other reducing sugars (fructose and galactose)

78
Q

air-fluid level in lung?

A

pulmonary abscess that communicates w/ air passage. allows for partial drainage of semiliquid exudate – air-containing cavity

79
Q

IFN-gamma is responsible for.

A

(1) phagolysosome formation (2) inducible nitric oxide synthase (3) development of granulomas & caseous necrosis

80
Q

what stimulates NK cells?

A

IL-12

81
Q

tissue damage from abscesses result from

A

lysosomal enzyme release from neutrophils and macrophages

82
Q

clara cells. describe histology & fxn.

A

non-ciliated, secretory constituents of terminal respiratory epithelium. release CCSP (clara cell secretory protein) which (1) inhibits neutrophil recruitment and activation, as well as (2) neutrophil-dependent mucin production.

83
Q

desquamative interstitial pneumona contains what cell type in alveolar spaces

A

actually alveolar macrophages.

84
Q

goblet cells are absent from what respiratory eptheium

A

terminal bronchiolar mucosa & alveoli

85
Q

when does tracheobronchial tree become a simple cuboidal ciliated epithelium?

A

level of respiratory bronchioles

86
Q

drug of choice for treating heroin addiction? why?

A

methadone: mu receptor agonist. potent, long acting, w/ good oral bioavailability. long half-life and sustained effects after chronic dosing allows for continuous suppression of withdrawal symptoms in heroin dependent patients – accumulates in tissue & slow releases after discontinuation.

87
Q

why is use of partial agonists (i.e. buprenorphrine) bad for treating heroin addiction?

A

can precipitate withdrawal

88
Q

rx for heroin withdrawal symptoms (rx for heroin addiction)? rx for heroin overdose? rx for heroin detoxification?

A

withdrawal & rx for addiction: methadone.

rx overdose: naloxone, altrexone

rx detox: buprenorphrine: partial agonist

89
Q

psychotic episodes for less than 1 mo? 1 - 6 months? greater than 6 mo?

A

> 1mo: brief psychotic episode.
1-6mo: schizophreniform
6mo: schizophrenia

90
Q

adjustment disorder

A

increased anxiety, depression, or disturbed havior that develops within 3 mo of an identifiable stressor & lasts no more than 6 months after.

91
Q

kawasaki’s disease is also known as

A

mucocutaneous lymph node syndrome.

vasculitis of medium sized arteries:

high fever, conjunctivitis, cervical lymphadenopathy, periungual desquamation, mucocutaneous changes (i.e. strawberry tongue)

92
Q

triad of HUS

A

(1) acute renal failure (2) microangiopathic hemolytic anemia (3) thrombocytopenia

93
Q

fluoxetine and other SSRI’s “off-label” use?

A

premature ejaculation

94
Q

monoamine oxidase:

A

MITOCHONDRIAL ENZYME. deaminates primary and secondary aromatic amines.

95
Q

side effect of amoxapine

A

TCA – mild parkinsonian symptoms

96
Q

describe etanercept

A

TNF-alpha inhibitor.

fusion protein linking a soluble TNF-alpha receptor to Fc component of human IgG1. reduces biological activity of TNF-alpha by acting as a decoy receptor.

97
Q

-nab, -cept, -nib means

A
  • mab: monoclonal anitobidy
  • cept: receptor molecule
  • nib: kinase inhibitor
98
Q

inflixamab

A

chimeric monoclonal ab against TNF-alpha. rx for autoimmune diseases like RA and Crohns

99
Q

certolizumab pegol

A

pegylated humanized monoclonal antibody to TNF-alpha. lacks Fc region (vs. etanercept)

100
Q

imatinib mesylate rx for (2)

A

(1) Ph+ CML and (2) c-kit + GIST (gastroinstestinal stromal tumors)

101
Q

c-KIT +

A

gastrointestinal stromal tumor

102
Q

germ tubes at 37 degrees

A

specific for c. ALBICANS. not for all candida

103
Q

candida-associated pulmonary disease

A

uncommon: common contaminant of sputum cultures.

104
Q

persistant bronchial asthma drug over long term

A

fluticasone.

105
Q

inhaled corticosteroids in acute episode?

A

inhaled corticosteroids have no role in acute exacerbations; high dose systemic is used.

106
Q

dopamine effects vary w/ dose. low?

A

LOW: renal & splanchnic vasodilation: stimulate D1 in renal vasculature –> increase GFR, RBF, and Na+ excretion.

MEDIUM: stimulate B1 in heart. increase cardiac contractility, pulse pressure, systolic BP.

HIGH: stimulate alpha1: generalized systemic vasoconstriction (decrease CO bc of increased afterload)

107
Q

dystrophic calcificaition is a hallmark..

A

of preceding cell injury & necrosis.

108
Q

most common sites of dystrophic calcification (2).

A

(1) damaged cardiac valve (2) atheromatous plaques

109
Q

describe process of dystrophic calcification (2)

A

(1) initiation: transpires within mitochondria of dead or dying cells.
(2) propagation: can eventually perforate the cell membrane from within

110
Q

gross dystrophic calcification? histological?

A

fine, gritty white granules / clumps. histology (H&E): dark purple, sharp-edged aggregates. called psammoma bodies when develops LAMELLATED outer layers.

111
Q

3 features distinguishing heart circulation from blood flow in skeletal muscle & viscera

A

(1) heart perfused in diastole & consumes approx 5% of cardiac output.

(2) myocardial oxygen requirement is high: capillary density exceeds all other tissue. OXYGEN EXTRACTION: at rest: 75-80% oxygen extracted. work: 90% extraction.
increase oxygen means increased FLOW.

(3) coronary flow is regulated by metabolic factors (hypoxia and adenosine): produce vasodilation & decreased vascular resistance.

112
Q

most deoxygenated blood is in..

A

coronary sinus. bc heart extraction of oxygen is so efficient.

113
Q

presentation of multiple myeloma (4)

A

presentation of..

(1) easy fatiguability (anemia)
(2) constipation (hypercalcemia)
(3) bone pain (back & ribs: production of osteoclast activating factor by myeloma cells)
(4) renal failure (azotemia)

114
Q

myeloma cast nephropathy

A

excess excretion of free light chains. most common form of nephropathy in MM patients.

bence jones protein (light chains) filtered by glomerulus, ppt w/ tamm horsfall protein, form eosinophillic cast

115
Q

eosinophillic casts in multiple myeloma?

A

bence jones protein + tamm horsfall protein

116
Q

elderly patient w/ multiple comorbidities, in admission process, must..

A

in any admission process: ask about advance planning, presence of advance directive, and what their wish should they enter terminal cardiac rhythm. ACUTE ISSUE

BEST discussed in outpatient setting, but readdress at admission.

117
Q

2 muscles in middle ear. fxn

A

stapedius & tensor tympani.

stapedius: arises from wall of tympanic cavity insets on neck of stapes. smallest striated muscle. stapedius n - branch of facial (CN VII). LESION: stapes oscillates too much; HYPERACUSIS

tensor tympani: arises from cartilagenous portion of auditory tube & adjoining part of sphenoid & insets into malleus. fxn: draw tympanic membrane medially – increasing tension. CN V3. lesion: HYPOACCUSISS

118
Q

inability to tolerate everyday sounds?

A

hyperacussis

119
Q

Kayser-Fleischer ring can be seen with..

A

most strongly associated w: WILSON’S DISEASE. also, chronic cholestatic disease (such as primary biliary cirrhosis). best identified w/ slit lamp, but can be seen grossly.

granular deposition of copper within descemet’s membrane in cornea

120
Q

wilson’s disease

A

rare, autosomal recessive, usu 5-40 y/o. genetic mutations hinder Cu2+ metabolism by reducing formation/secretion of ceruloplasmin & decreasing secretion of Cu2+ into the biliary system.

Cu2+ –> pro-oxidant and causes hepatic injury. leaks from injured hepatocytes into circulation, deposited in various tissues (CORNEA and BASAL GANGLIA –> ATROPHY)

121
Q

rx for wilson’s disease?

A

d-penicillamine & trientine

122
Q

3 things that left-shift oxygen dissociated curve

A

LEFT = LUNG

(1) decrease 2,3 DPG
(2) decreased temp
(3) decreased H+

123
Q

what causes 2,3 DPG to increase?

A

2,3 DPG is an organophosphate created in erythrocytes during glycolysis. made when oxygen availability is reduced (chronic lung disease, heart failure, chronic exposure to high altitudes).

elevated 2,3 DPG decrease hemoglobin’s affinity (right shift)

124
Q

most likely outcome w/ HCV infxn? death usu due to?

A

asymptomatic & mild symptoms that resolve within a few weeks. 55-85%, STABLE CHRONIC IFXN with HCV develops, with persistent elevation of liver enzymes.

complete resolution in a minority (15-45%)

progression to fulminant hepatitis, rare

< 50% cirrhosis silently.

hepatocellular carcinoma: annual risk is 0-3%.

death due to end stage liver disease (vs. hepatocellular carcinoma)

125
Q

when does QRS complex occur in cardiac ventricular myocyte action potential?

A

phase 0 (rapid sodium movement into the cardiac myocyte)

126
Q

HGPRT deficiency in lesch nyhan results in

A

deficiency in purine salvage pathway. PRPP builds up – shunts to purine de novo pathway. 1st step: PRPP amidotransferase. commits PRPP to de novo purine synthesis

127
Q

ribonucleotide reductase

A

required in de novo purine synthesis. convert ribose - deoxyribose (purine and pyrimidine nucleosides)

128
Q

chronic myeloproliferative disorders (3) & common mutation

A

(1) polycythemia vera. (2) essential thrombocytosis. (3) primary myelofibrosis.

mutation V617F in cytoplasmic tyrosine kinase (JAK2). constitutive tyrosine kinase activity –> cytokine-independent activation of STAT transcription factors

129
Q

primary myelofibrosis

A

type of myeloproliferative disorder (JAK2) caused by atypical MEGAKARYOCYTE hyperplasia. stimulate FIBROBLASTS. secrete excess COLLAGEN.

early: hypercellular w/ minimum fibrosis. later –> loss of bone marrow

130
Q

CLL is associated w/ increase in which gene expression

A

Bcl-2, like follicular lymphoma

131
Q

rx for primary myelofibrosis:

A

ruxolitinib (JAK2 ihibitor)

UWorld mixed (60 decks)

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